UFC president Dana White announced at Friday’s post-UFC on FX 3 press conference that Penn vs. MacDonald will happen, and that the pair will likely serve as the co-main event of UFC 152 in Toronto.

“We’re going to do it,” White said when asked about the rumored fight.

White said UFC matchmaker Joe Silva was expected to talk with both fighters on Friday night and finalize the bout.

UFC 152 takes place Sept. 22 at Air Canada Centre in Toronto. Currently, no
headliner has been set for the pay-per-view card.

MacDonald issued the challenge to Penn on Monday’s edition of The MMA Hour.

“Right now I feel there’s a guy that I want to fight before he leaves the sport, and that’s B.J. Penn,” MacDonald said on the MMAFighting.com show. “That’s a guy I really want to fight. I respect him a lot. He’s a legend, and I think it’d be a really good matchup for me to have that fight in Toronto.”

Penn later responded and said he accepted MacDonald’s challenge.

MacDonald is riding a three-fight win streak in the UFC. Following victories over Nate Diaz and Mike Pyle, he co-headlined April’s UFC 145 event and submitted Che Mills with strikes. The 22-year-old’s only trip-up came in his second UFC fight, when Carlos Condit knocked him out at UFC 115 in a “Fight of the Night” performance.

MacDonald, a Tristar Gym member, said he won’t fight his training partner: current welterweight champion Georges St-Pierre. However, with a victory over a notable name such as Penn, he could be knocking on the door of a title shot.

Penn, though, is in a bit of a funk and is just 1-3-1 in his past five fights. The skid included losing his lightweight title (and a rematch) to Frankie Edgar. Following an October loss to welterweight Nick Diaz at UFC 136, Penn effectively retired from MMA, though White kept the door open for the 33-year-old’s return.